Control for electric circuits



Nov, 13, 1928, lfiifiififiti a. MUFFLY CONTROL FOR ELECTRIC CIRCUITSFiled Nov. 26, 1926 AV VE/V T01? GLE/V/V NUFFL Y 1; y %*7 A TTOf NE 1/35 indicated generally as having Patented Nov. 13, 1928.

UNITED STATES GLENN MUFFLY, OE DETROIT, MICHIGAN.

CONTROL FOB ELECTRIC CIRCUITS.

Application filed November 26, 1926. Serial No. 150,714.

It is the primary object of my invention to provide a control foralternately making and breaking an electric circuit in response tovarying conditions. My device is articular- 5 1y adapted for use iniceless re rigeration systems where it is desired to make and break theelectric circuit to an electric motor in response to temperaturevariations.

My device embodies a tube containingmercury, which, when shifted, makesand breaks a circuit between two contact points and an important featureof my invention is the provision of means for snapping the mercury tubeto on and off position so that the action of the device will be quickand positive.

Another object is to combine with the mercury tube or other make andbreak device and the snapping device a means for adjusting by springtension the point at which the snapping device will make its snapover.

With the above and other objects in view,

my invention consists 'in the arrangement,

combination and construction of the variousparts of my improved device,as described in the specification, claimed in my claims, and

. shown in the accompanying drawings, in which:

Fig. 1 is a sectional view of my improved device mounted on the top of arefrigerator casing or box, with a portion thereof extended into thebox.

Fig. 2 is a top or plan view of my improved device.

I have shown a refrigerator casing or box a top 6 through which a tube"?is extended. The bottom of the tube 7 is enlarged as at 8 and is adaptedto receive a quantity of material, such as sulphur dioxide whichliquefies in the presence of cold and gasifies in the presence of heat.

The top of the tube 7 extends through an opening 9 in a base member 10mounted on the top of the refrigerator box. A sylphon or 4 bellows 11 ismounted on the base 10 having its lower end closed by a plate 12. Theplate 12 is provided with a central flanged aperture, the flange beingindicated at 13, which flange 13 surrounds the top of the tube 7 and issealed 5 thereto in any suitable manner. such as by soldering. The topof the bellows 11 is integral with the sides thereof so as to provide aclosed structure. A plate 14 is disposed over the bellows 11, said platehaving a notch 15 in one end thereof engaged by the central portion of aU clamp 16 secured to the base 10 by nuts 17. Thus the U clamp 16 holdsthe plate 14 as at 15 at one end thereof against upward movement. Theother end of the plate 14 is provided with an aperture 18 through whicha bolt 19 extends. The bolt 19 is provlded with a head 20 which bears onthe base 10 and has a nut 21 on the lower end thereof for securing thebolt to the base 10 in co-operation with the head 20. A coil spring 22is provided around the bolt 19 above the plate 14, bearing at its bottomon the plate and at its top against a cuplike washer 23 which is securedon the bolt 19 by means of nuts 24. Thus upward movement of the free endof the plate 14 is resisted by the spring 22 and the amount ofresistance to such movement may be controlled by adjustment of the nuts24.

A spring support member comprising an upright portion 25 and a bowedportion 26, integral with the upright portion, is positioned on the base10, being secured by a stud 27 having a head 28 hearing against thebowed portion and having its shank threaded into the boss 29 on the base10. Extended through an opening 30 adjacent the top of the uprightportion 25 is a plate 31 which has secured to its other end by means ofclips 32 a mercury tube 33. The plate 31 is secured intermediate itsends to a flat spring 34 by a rivet 35. The spring 34 is also secured bya rivet 36 to the movable end of the plate 14.

A pair of clamping plates 37 and 38 are secured to the base 10 by ascrew 39 and a pair of electric lead lines 40 and 41 are secured betweenthe clamping plates. These lead lines extend to and within the mercurytube 33- where the contact points 42 and 43 are formed thereon. Thesecontact points are positioned in one end of the tube 33 so that amercury drop 44 may connect them when the tube is so tilted so as tobring the mercury drop to that end of the tube in which the terminalsare positioned.

'In the practical operation of my device heat contained in therefrigerator box 5 will gasify the sulphur dioxide or other suitablematerial in the enlar ed portion 8 of the tube 7 with the result thatthe gas so formed will expand the bellows 11, causing the plate 14 topivot about the head of the U clamp 16, raising the other end thereofagainst the pressure of the spring 22. Raising of one end of the plate14 will likewise raise that end of the spring 34 which is connected tothe plate 14 and'tilt the mercury tube 33 as is shown in Fig. 1. It willbe seen that the spring 34 is buckled between the rivets and 36 and whenthe temperature in the refrigerator box 5 is lowered the sulphur dioxidewill be liquefied and pressure decreased in the bellows 11, with aconsequent lowering of the plate 14 by the pressure of the spring 22until a reverse buckle in the spring 34 is caused as is shown in dottedlines in Fig. 2. This reverse buckle is obtained by snapping the spring34 from one position to the other, it being apparent that, because it isbuckled, movement from one extreme position to the other cannot be agradual one. The spring standard 25 and bowed portion 26 may be aptedupon by the stud 28 for adjusting the amount of how in the spring 34.Likewise adjustment of the amount of pressure required to move the plate14 may be had by adjusting the tension on the spring 22.

I desire it to be understood that my invention may be employed in otherthan electric circuits for refrigeration systems and that other devicesfor making and breaking the circuit may be employed than mercury tubes.

It will be obvious that various changes may be made in the arrangement,combination and construction of the various parts of my improved devicewithout departing from the spirit of my invention, and it is myintention to cover by my claims such changes as may be included withinthe scope thereof.

What I claim is:

1. A control of the class described comprising a bellows adapted to beexpanded and contracted in response to pressure variations, a plateoverlying one end of the bellows and adapted to be movedby it, a flatspring member connected at one end to said plate and at the other end toa standard, said spring being held in arched position and being snappedfrom an arch in one direction to an arch in the other as said bellowsexpands and contracts, and a circuit make and break device connectedwith the spring and adapted to be actuated by its change of arch.

2. A control of the class described comprising a bellows adapted to beexpanded and contracted in response to pressure variations, a plateoverlying one end of the bellows and adapted to be moved by it, a flatspring member connected at one end to said plate and at the other end toa standard, said standard being provided with an arched bottomextension, a stud extended through the arched extension, said stud beingadjustable to exert varying pressures on the arched extension andthereby vary the angle at which the standard extends, said spring beingheld in arched position and being snapped from an arch in one directionto an arch in the other as said bellows expands and contracts, and acircuit make and break device connected with the spring and adapted tobe actuated by its change of arch.

3. A control of the class described comprising a bellows adapted to beexpanded and contracted in response to pressure variations, a plateoverlying one end of the bellows and adapted to be moved by it, a flatspring member connected at one end to said plate and at the other end toan adj ustably tiltable standard, said spring being held in archedposition and being snapped from an arch in one direc tion to an arch inthe other as said bellows expands and contracts, and a circuit make andbreak device connected with the spring and adapted to be actuated by itschange of arch.

4. A control of the class described comprising a bellows adapted to beexpanded and contracted in response to pressure variations,

a plate overlying one end of the bellows and adapted to be moved by it,a flat spring member connected at one end to said plate and at the otherend to a standard. said spring being held in arched position and beingsnapped from an arch in one direction to an arch in the other as saidbellows expands and contracts, a' circuit make and break deviceconnected with the springand adapted to be actuated by its change ofarch, and spring means bearing against said plate to resist expansionmovement of the bellows and follow contraction movement thereof.

5. A construction as set forth in claim 1 wherein said flat spring isconnected to the plate on one side of the bellows and an anchor isconnected thereto on the other.

6. A construction as set forth in claim 1 wherein said fiat spring isconnected to the plate on one side of the bellows, and an anchor isconnected thereto on the other, said anchor comprising a U shaped memberhaving its ends secured to a suitable support and its intermediateportion looped over a portion of the plate.

7 A control of the class described comprising a bellows adapted to beexpanded and contracted in response to pressure variations, a plateoverlying one end of the bellows and adapted to be moved by it, a fiatspring member connected at one end to said plate and at the other end toa standard, means for applying adjustable spring tension on thestandard, said spring being held in arched position and being snappedfrom an arch in one direction to an arch in the other as said bellowsexpands and contracts. and a circuit make and break device connectedwith the spring and adapted to be actuated by its change of arch.

' GLENN MUFFLY.

